Imager with tuned color filter

ABSTRACT

An optimized color filter array is formed in, above or below a one or more damascene layers. The color filter array includes filter regions which are configured to optimize the combined optical properties of the layers of the device to maximize the intensity of the particular wavelength of light incident to a respective underlying photodiode.

FIELD OF THE INVENTION

[0001] The present invention relates to improved semiconductor imagingdevices and, in particular, to CMOS imagers with improved color filters,color separation and sensitivity.

BACKGROUND OF THE INVENTION

[0002] Color imaging in solid state or digital video cameras istypically performed with different types of semiconductor-based imagers,such as charge coupled devices (CCDs), complementary metal oxidesemiconductor (CMOS) photodiode arrays, charge injection devices andhybrid focal plane arrays, among others.

[0003] A CMOS imager circuit generally includes an array of microlenses, color filters and a photo imager which converts a color filteredlight signal into a digital form using a read out array and digitalprocessing. The photo imager portion of the imager includes a focalplane array of pixels, each one of the pixels including either a lightsensitive area such as a photogate, photoconductor or a photodiodeoverlying a doped region of a substrate for accumulating photo-generatedcharge in the underlying portion of the substrate. A readout circuit isconnected to each pixel and includes at least an output field effecttransistor formed in the substrate and a charge transfer section formedon the substrate adjacent the photogate, photoconductor or photodiodehaving a sensing node, typically a floating diffusion node, connected tothe gate of an output transistor. A device layer above or surroundingthe photo sensitive regions contains wire connections to the photodiodesand some or all of the elements of a read-out circuit among otherthings. The imager may include at least one electronic device such as atransistor for transferring charge from the charge accumulation regionof the substrate to the floating diffusion node and one device, alsotypically a transistor, for resetting the node to a predetermined chargelevel prior to charge transference.

[0004] Color imaging photodiode systems suffer from a variety ofproblems. For example, light intensity losses at the photo sensitiveareas area due to absorption or diffraction occur as light enters themicro lenses, passes through a color filter as well as interveninglayers until incident light passes into the light sensitive area of aphotodiode or photogate.

[0005] Optical distortion causing, among other things, light intensitylosses result from a number of design factors. Pixel surfaces above aphotodiode are constructed to include, for example, color filters forred, green, blue, or cyan, magenta or yellow, depending on technologyused, which are delineated on a flat planar surface. The light receivedby a photodiode is influenced by the materials and depths of a substrateabove the photodiode. The intensity of light which reaches a photodiodewhich is underneath a stack of layers on an imager device is dependenton the wavelength of the light which is transmitted through colorfilters and or substrates due to thin film interference effects andindex of refraction changes based on the depths and materials used inthe imager's substrate.

[0006] Some designs vary the distance of the photodiode from the topsurface of the imager in an effort to adjust for the effects ofrefraction and absorption within the substrate above a photodiode.Varying the photodiode distance from the top surface of the imagergreatly increases the cost of imager manufacturing. Such complexity addsto design costs and does not adequately address design limitations onthe ultimate transmission of photons to the light sensitive area of aphotodiode or adequately increase the maximum photon intensity which canbe captured by a given photodiode. Thus, a new approach is needed whichcan enable simplified photodiode construction while still improving oroptimizing photon transmission to various photodiodes which receivedifferent wavelengths of light, e.g., blue, red or green.

BRIEF SUMMARY OF THE INVENTION

[0007] The present invention provides alternative processes formanufacturing color imager pixel structures for optimizing transmissionof light to various photodiodes which receive different wavelengths oflight such as blue, green or red. Various methods of forming a colorfilter array are provided which incorporate different processing schemesincluding a single etch, multiple etches and various color filterelement formation processes including various masking procedures inconjunction with etching and forming a color filter element. A varietyof approaches are used to obtain optimized transmission of light throughlayers of the imager including adjusting color filter windows in adamascene layer for each pixel to optimize light incident at the colorfilter. Another embodiment provides for extended color filter layerswhich rise above a device layer such that each color filter layer isoptimized in dimension and possibly material for each photodiode whichabsorbs a particular wavelength of light (e.g., red, green, blue).Damascene layers are used which provide room in which various colorfilter cavities may be formed to dimensions that provide optimizedoptical characteristics for light absorbed by a particular photodiode.Varied color filter cavities can also be formed within the overheadportion of device layers immediately above a photodiode if sufficientheadroom is available in a device layer. Various types of damascene orlayer adjustments are possible including the use of encapsulation layersabove and below color filter elements which adjust optical properties ofthe combined layers above a particular diode by changing combined layeroptical properties or by moving a color filter element in relation to aparticular photodiode or light sensitive region.

[0008] These and other features and advantages of the invention will bebetter understood from the following detailed description, which isprovided in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1A shows a cross sectional view of an exemplary color pixeland filter structure before processing in accordance with one exemplaryembodiment of the invention;

[0010]FIG. 1B shows a cross sectional view of the FIG. 1A color pixeland filter at a state of processing subsequent to that shown in FIG. 1A;

[0011]FIG. 1C shows a cross sectional view of the FIG. 1A color pixeland filter at a state of processing subsequent to that shown in FIG. 1B;

[0012]FIG. 1D shows a cross sectional view of the FIG. 1A color pixeland filter at a state of processing subsequent to that shown in FIG. 1C;

[0013]FIG. 1E shows a cross sectional view of the FIG. 1A color pixeland filter at a state of processing subsequent to that shown in FIG. 1D;

[0014]FIG. 1F shows a cross sectional view of the FIG. 1A color pixeland filter at a state of processing subsequent to that shown in FIG. 1E;

[0015]FIG. 2A shows a cross sectional view of an exemplary color pixeland filter structure before processing in accordance with one exemplaryembodiment of the invention;

[0016]FIG. 2B shows a cross sectional view of the FIG. 2A color pixeland filter at a state of processing subsequent to that shown in FIG. 2A;

[0017]FIG. 2C shows a cross sectional view of the FIG. 2A color pixeland filter at a state of processing subsequent to that shown in FIG. 2B;

[0018]FIG. 2D shows a cross sectional view of the FIG. 2A color pixeland filter at a state of processing subsequent to that shown in FIG. 2C;

[0019]FIG. 2E shows a cross sectional view of the FIG. 2A color pixeland filter at a state of processing subsequent to that shown in FIG. 2D;

[0020]FIG. 2F shows a cross sectional view of the FIG. 2A color pixeland filter at a state of processing subsequent to that shown in FIG. 2E;

[0021]FIG. 2G shows a cross sectional view of the FIG. 2A color pixeland filter at a state of processing subsequent to that shown in FIG. 2F;

[0022]FIG. 3A shows a cross sectional view of an exemplary color pixeland filter structure before processing in accordance with one exemplaryembodiment of the invention;

[0023]FIG. 3B shows a cross sectional view of the FIG. 3A color pixeland filter at a state of processing subsequent to that shown in FIG. 3A;

[0024]FIG. 3C shows a cross sectional view of the FIG. 3A color pixeland filter at a state of processing subsequent to that shown in FIG. 3B;

[0025]FIG. 3D shows a cross sectional view of the FIG. 3A color pixeland filter at a state of processing subsequent to that shown in FIG. 3C;

[0026]FIG. 3E shows a cross sectional view of the FIG. 3A color pixeland filter at a state of processing subsequent to that shown in FIG. 3D;

[0027]FIG. 3F shows a cross sectional view of the FIG. 3A color pixeland filter at a state of processing subsequent to that shown in FIG. 3E;

[0028]FIG. 3G shows a cross sectional view of the FIG. 3A color pixeland filter at a state of processing subsequent to that shown in FIG. 3F;

[0029]FIG. 3H shows a cross sectional view of the FIG. 3A color pixeland filter at a state of processing subsequent to that shown in FIG. 3G;

[0030]FIG. 3I shows a cross sectional view of the FIG. 3A color pixeland filter at a state of processing subsequent to that shown in FIG. 3H;

[0031]FIG. 3J shows a cross sectional view of the FIG. 3A color pixeland filter at a state of processing subsequent to that shown in FIG. 3I;

[0032]FIG. 3K shows a cross sectional view of the FIG. 3A color pixeland filter at a state of processing subsequent to that shown in FIG. 3J;

[0033]FIG. 4A shows a cross sectional view of an exemplary color pixeland filter structure before processing in accordance with one exemplaryembodiment of the invention;

[0034]FIG. 4B shows a cross sectional view of the FIG. 4A color pixeland filter at a state of processing subsequent to that shown in FIG. 4A;

[0035]FIG. 4C shows a cross sectional view of the FIG. 4A color pixeland filter at a state of processing subsequent to that shown in FIG. 4B;

[0036]FIG. 4D shows a cross sectional view of the FIG. 4A color pixeland filter at a state of processing subsequent to that shown in FIG. 4C;

[0037]FIG. 4E shows a cross sectional view of the FIG. 4A color pixeland filter at a state of processing subsequent to that shown in FIG. 4D;

[0038]FIG. 4F shows a cross sectional view of the FIG. 4A color pixeland filter at a state of processing subsequent to that shown in FIG. 4E;

[0039]FIG. 4G shows a cross sectional view of the FIG. 4F color pixeland filter at a state of processing subsequent to that shown in FIG. 4F;

[0040]FIG. 5A shows a cross sectional view of a portion of a color pixelstructure before processing in accordance with one exemplary embodimentof the invention;

[0041]FIG. 5B shows a cross sectional view of the FIG. 5A color pixeland filter structure at a state of processing subsequent to that shownin FIG. 5A;

[0042]FIG. 5C shows a cross sectional view of the FIG. 5A color pixeland filter structure at a state of processing subsequent to that shownin FIG. 5B;

[0043]FIG. 5D shows a cross sectional view of the FIG. 5A color pixeland filter structure at a state of processing subsequent to that shownin FIG. 5C;

[0044]FIG. 5E shows a cross sectional view of the FIG. 5A color pixeland filter structure at a state of processing subsequent to that shownin FIG. 5D;

[0045]FIG. 6A shows a cross sectional view of a portion of a color pixelstructure before processing in accordance with one exemplary embodimentof the invention;

[0046]FIG. 6B shows a cross sectional view of the FIG. 6A color pixeland filter structure at a state of processing subsequent to that shownin FIG. 6A;

[0047]FIG. 6C shows a cross sectional view of the FIG. 6A color pixeland filter structure at a state of processing subsequent to that shownin FIG. 6B;

[0048]FIG. 6D shows a cross sectional view of the FIG. 6A color pixeland filter structure at a state of processing subsequent to that shownin FIG. 6C;

[0049]FIG. 6E shows a cross sectional view of the FIG. 6A color pixeland filter structure at a state of processing subsequent to that shownin FIG. 6D;

[0050]FIG. 6F shows a cross sectional view of the FIG. 6A color pixeland filter structure at a state of processing subsequent to that shownin FIG. 6E;

[0051]FIG. 6G shows a cross sectional view of the FIG. 6A color pixeland filter structure at a state of processing subsequent to that shownin FIG. 6F;

[0052]FIG. 7A shows a cross sectional view of a portion of a color pixelstructure before processing in accordance with one exemplary embodimentof the invention;

[0053]FIG. 7B shows a cross sectional view of the FIG. 6A color pixeland filter structure at a state of processing subsequent to that shownin FIG. 7A;

[0054]FIG. 7C shows a cross sectional view of the FIG. 6A color pixeland filter structure at a state of processing subsequent to that shownin FIG. 7B;

[0055]FIG. 8 shows a cross sectional view of an exemplary embodiment ofa portion of a color pixel and filter structure showing exemplary layersin the structure;

[0056]FIG. 9 shows an block diagram of a computer processor systemincorporating an imager device having an array of pixels fabricatedaccording to the present invention;

[0057]FIG. 10 shows a processing sequence for manufacturing a colorpixel and filter element in accordance with an exemplary embodiment theof invention;

[0058]FIG. 11 shows a processing sequence for manufacturing a colorpixel and filter element in accordance with an exemplary embodiment ofthe invention;

[0059]FIG. 12 shows a processing sequence for manufacturing a colorpixel and filter element in accordance with an exemplary embodiment ofthe invention;

[0060]FIG. 13 shows a processing sequence for manufacturing a colorpixel and filter element in accordance with an exemplary embodiment ofthe invention;

[0061]FIG. 14 shows a processing sequence for manufacturing a colorpixel and filter element in accordance with an exemplary embodiment ofthe invention; and

[0062]FIG. 15 shows a processing sequence for manufacturing a colorpixel and filter element in accordance with an exemplary embodiment ofthe invention.

DETAILED DESCRIPTION OF THE INVENTION

[0063] One aspect of the invention provides for an alternativeprocessing scheme for forming a color filter array for imager sensors.Another aspect of the invention permits the use of current devicemanufacturing techniques for tuning specific areas of the substrate formaximum color transmission.

[0064] An exemplary embodiment uses a damascene type of processing toform a color pixel rather than a direct lithographic imaging of a colorfilter resist. Color filter array (CFA) cavities for pixels aregenerated by conventional lithography and etch in oxide or anothersuitable matrix material which are then filled with a colored material.During a subsequent chemical mechanical processing (CMP) process, allcolored material will be removed except for the recessed areas, whichremain filled to form the color filter portion of the pixels.

[0065] Colored material depths used in color filters can be varied totune the optical properties of a particular photo sensitive region ofthe imager array. A damascene layer can be used to provide sufficientroom above a diode and/or metallization layer above a diode so that theoptical properties of the layers above the diode can be varied in orderto optimize incident light at the diode for a particular wavelength. Adamascene layer may not be required when there is sufficient headroomfor a color filter cavity to extend into the layer above the photodiodeif needed for optical property adjustment.

[0066] Recessed areas in a damascene layer and possibly other layersabove a photodiode create a color filter array (CFA) window or filtersection above a photodiode as well as portions of the substrate,including a device stack and damascene layers. The use of a CFA windowto alter the collective thin film interference, refractive andabsorptive properties of the various materials above the photodiodeincreases the maximum intensity of a particular wavelength range oflight which is received at the photodiode. Also, a high resolution andprint quality can be obtained from a pixel incorporating an optimizedCFA window as high resolution standard resists can be used with standardlithography technology, unlike lithographic formation of color pixelsusing direct color resist imaging. Also, color material applied withstandard coating technology and using a damascene style structure and aCFA window does not have to be imagable, and therefore provides a muchlarger freedom in chemical formation and material constraints. Also,thinner color films can be used with higher pigment loading, whichimproves optics of some imager designs. Moreover, use of the inventionpermits fully planarized color matrix structures despite the ability toadjust damascene and CFA window layer thickness' for each colorindividually. Problems such as color streaking due to topography ofprevious colors adversely affecting another pixel structure are avoided.Optical cross talk can also be reduced due to shallower overall filmstacks and thus aspects of the invention offers an option to increaseseparation or create a separation matrix between pixels. An aspect ofthe invention also prevents color residues on neighboring pixels andoffers lower cost color materials for fabrication of the CFA. Also, theinvention permits the elimination of a need for isolated photofabrication areas which is currently required due to resistcontamination with mobile ions caused by conventional CFA fabricationprocesses. Lastly, the invention offers a built-in lens above orunderneath the color pixel without the need for an additionalplanarizing coat. The invention also permits a wide variety ofstructures which afford the requisite “tuning” of the collectiverefractive and absorptive properties of the layers above a photodiode.

[0067] Modeling of the thin film interference, refractive and absorptiveproperties of all layers above a photodiode of an imager is accomplishedto begin analysis of wavelength tuning which will be required. Modelingof refractive and absorptive properties of photodiode and imager layersis well known in the art. For example, commercial software such asMathCAD, Prolith or SolidC are available which calculates multiplereflectivities and absorption of multiple films sitting on top of eachother. Commercial lithography software can also be used. A designerinputs the basic optical parameters of the various films, then thesoftware outputs the fraction that is absorbed, as well as how much isreflected and how much is absorbed. Manual calculations can be used aswell employing software applications using Snells refractive equation,Fresnel's equations as well as Beer Lambert equations which discuss bulkabsorption of films, which have an exponential relationship whereabsorption increases exponentially as thickness increases.

[0068] Generally, a variety of solutions are determined and an optimumchoice is selected. After determining the optimum set of layers,including the variable CFA window dimensions as well as materials ifneed be, then one of a number of etching approaches is applied and acolor pigment filler is placed within the CFA window cavity. In someexemplary embodiments, different CFA window dimensions and material foruse in the CFA window cavity may be used to optimize reflectivity andabsorption properties of an imager stack above the photosensitive areaof a diode. Providing for the use of a damascene layer, as well asvariable depth CFA window through a damascene, and in some cases, thedevice layer of an imager above a diode and underneath the damascenelayer, permits the creation of the CFA window of various dimensionswhich optimize reflectivity and other optical properties of an imager.In other words, a CFA window, or the cavity with color filler, mayextend through a portion of the damascene layer as well as, in somecases, into the substrate stack leading down to the photodiode. CFAwindows can be used with complementary colors photodiode assemblies aswell. Determination of thickness of a particular CFA window andunderlying layer(s) above an underlying photodiode is dependent on,among other things, the color filter used on top of the photodiode andrefractive index of the combined stack including the CFA window, and allother layers above the photodiode, through which incident photons mustpass. The thickness of a particular CFA window can also be based in parton a micro lens which is used with a pixel or imager assembly in orderto adjust for optical focus or other lens attributes. A CFA window canalso be used which extends above a device layer or damascene layer aswell, rather than down into a damascene or device layer. A designer candetermine an optimal thickness using a computer or manual interference,refractive or absorptive model of a given stack or set of layers above aphotodiode to maximize intensity of light arriving at the photodiode.

[0069] A first embodiment can be created with photosensitive colormaterials to form differently colored pixels inside a previously definedhard matrix material which is above photodiodes of a color pixel. Thehard matrix material is etched to open all three CFA cavities for thecolor filter material. Each color can be added sequentially by coatingthe full wafer with the selected color and imaging it with a maskpattern that removes the unwanted color material in the previouslydefined cavities in a develop step. After two colors have been imaged,the third pixel type can be formed by coating the third color andpolishing the wafer, without an additional imaging step, until threeseparately colored pixels remain in the cavities of the matrix.

[0070] Referring to FIG. 1A, the first embodiment begins with aplurality of photodiodes 9 formed on a substrate 11. A region 7comprising oxide and metal layers are formed on and around photodiodes9. A hard matrix material layer 5 is formed above the oxide and metallayers 7. A layer of photo resist 3 is formed above the matrix materiallayer 5. Referring to FIG. 1B, the photo resist layer 3 is imaged andcavities are made in the photo resist layer above photodiodes 9 using astandard resist process. Referring to FIG. 1C, the matrix material layer5 is etched, remaining photo resist 3 is stripped and a first photosensitive color coating 15 is applied (e.g. a red color coating) intothe cavities in matrix layer 5. The photo sensitive color coating 15 isexposed and developed to remove color coating from cavities 16, 17 whichare to receive other color coatings. Referring to FIG. 1E, chemical andmechanical polishing (CMP) is accomplished on the applied 15 to bringthe coating 15 level with the matrix layer 5. Referring to FIG. 1F, theprocess of application of color, stripping the color from cavities(i.e., 16, 17) which are to receive another color coating (i.e., 19,20), then CMP processing, is repeated until all coating layers 15, 16and 17 are applied and the coatings processed.

[0071] Referring to FIG. 10, one exemplary process for manufacturing anembodiment of the FIG. 1F pixel structure is shown. At processingsegment S111, an initial film stack is formed including a substrate 11,photodiodes 9 formed on the substrate 11, a device layer 7 around thephotodiodes 9, a hard matrix material 5 above the device layer 7 and aphoto resist layer 3 formed above the hard matrix material 5. Atprocessing segment S113, cavities are formed in the photo resist layer 3by imaging above all of the photodiodes 9 using a standard resist. Atprocessing segment S115, the hard matrix layer 5 underneath thepreviously formed cavity is etched and stripped. At processing segmentS117, a photosensitive color coating 15 (e.g., red) is applied overremaining hard matrix layer 5 and into the previously formed cavities.At processing segment S118, the color coating 15 is exposed anddeveloped to remove color coating 15 and form cavities 16, 17 (FIG. 1D)over two of the three photodiodes 9. At processing segment S119, CMP andcleaning is accomplished to remove remaining color material 15 above thelevel of the hard matrix material 5. At processing segment S120, it isdetermined if another color coating is required. If another colorcoating is required, then a different photo sensitive color coating 19(e.g., green or blue) is applied over remaining hard matrix layers 5,layer 15 and into cavities 16, 17 at step S117. Then, at processingsegment 109, the photo sensitive color coating 19 is exposed anddeveloped above the photodiodes 9 without a color coating. At processingsegment S119, the color coating applied at processing segment S118 isprocessed by CMP and cleaned so that the top surface of color coating 19is even with the remaining hard matrix layer 5. At processing segmentS120, another determination is made as to whether or not another colorcoating is required. If another color coat is required, then processingsegments S117 through S119 are repeated using another photo sensitivecolor coating (e.g., 20 FIG. 1F). If, at processing segment S120, it isdetermined that no further color coatings are required, processingterminates.

[0072] A second embodiment of the invention is formed with separate hardmatrix etches for each color and uses three separate cavities, one percolor, that are used to open and fill holes in the matrix material 5 bythree sequential photo, etch, coat and polish steps. For each color, acoating is applied to a wafer with standard photo resist, imaging itwith a lithography tool to remove the resist in the intended pixel areasand etching the open areas in a dry etch tool. The wafer then getscoated with color resist and the remaining resist, except the color inetched areas, is removed. Additional cavities are formed in the hardmatrix then a color coating is applied, then removed in the mannerdescribed above until all color filters are formed.

[0073] Referring to FIG. 2A, the second embodiment begins to be formedwith photodiodes 8, 9 and 10 on a substrate 11. Region 7 comprisingoxide and metal layers is formed on and around photodiodes 8, 9 and 10.A hard matrix material layer 5 is formed above the oxide layer 7. Alayer of photo resist 3 is formed above the matrix material layer 5.Referring to FIG. 2B, the photo resist layer 3 is imaged and a cavity 21is made in the photo resist layer 3 above a photodiode 8 using astandard resist process. As shown in FIG. 2C, the matrix material layer5 is etched to form a cavity 22 and the photo resist is stripped.Referring to FIG. 2D, a first photo sensitive color coating 23 isapplied (e.g. a red color coating) into cavity 22 and on top of matrixlayer 5. Referring to FIG. 2E, chemical and mechanical polishing (CMP)is accomplished on the applied color coat 23 to bring the coating 23level with the matrix layer 5. Referring to FIG. 2F, a photo resistlayer 24 is applied to the top of remaining color coating 23 and matrixlayer 5. The process of a separate matrix etch for each color (e.g., 26then 27) is repeated to produce a resulting exemplary embodiment asshown in FIG. 2G. FIG. 2G shows depths of color coatings 23, 35 and 26to be uniform. It should understood that color coating (e.g., 23, 25 or26) depths can be varied to selectively adjust the combined opticalproperties of layers above a respective photodiode 8, 9 or 10.

[0074] Referring to FIG. 11, one exemplary process for manufacturing anexemplary embodiment of the FIG. 2F structure using a single matrix etchper color is shown. At processing segment S121, an initial film stack isformed including a substrate 11, photodiodes 8, 9, 10 formed on thesubstrate 11, a device layer 7 around the photodiodes (8, 9, 10), a hardmatrix material 5 above the device layer 7 and a photo resist layer 3formed above the hard matrix material 5. At processing segment S123, acavity 21 (FIG. 2B) above a photodiode 8 is imaged in the standardresist 3. At processing segment S125, the hard matrix layer 5 belowcavity 21 (FIG. 2B) and photodiode 8 is etched and stripped to form acavity 22 (FIG. 2C) in the matrix layer 5. At processing segment S127, acolor coating 23 (FIG. 2D) (e.g, red, green or blue) is applied overmatrix layer 5 and in cavity 22. At processing segment S131, the colorcoating 23 above the level of the matrix layer 5 is removed using amethod such as CMP. A determination of whether or not another colorcoating is needed is made at processing segment S133. If another colorcoating is needed, then photo resist 24 will be applied on top of thepreviously applied color material (e.g., FIG. 2F, 23) and the remaininghard matrix material 5. Then processing continues from processingsegment S123 to create a cavity in photo resist (e.g., 24), create acavity in hard matrix material over a photodiode (e.g., 9 or 10), applya different color coating (e.g., green or blue), following removal ofcolor coating above the level of the matrix layer 5. Anotherdetermination is made of whether or not another color coating isrequired at processing segment S133. If another color coat is required,then processing commences at processing segment S135 through segmentS131. If another color coating is not required at processing segmentS133, then processing stops.

[0075] A third embodiment provides for imaging and etching cavities intothe hard matrix for all pixels at once with a common depth for allcolors. The wafer is then coated with photo resist and one cavity isexposed and developed. The wafer is coated with a color then theunwanted portions of the color removed. Another layer of photo resist isapplied over a pixel then removed from the next cavity over a photodiodeto be filled with the next color material. A coating of color materialis applied over the pixel then polished to remove excess color material.The remaining cavity to be processed will be exposed and developed toremove photo resist from the cavity. Another color layer is applied overthe pixel and into the remaining cavity without color material. Thecolor layer is then polished to remove undesired color material.

[0076]FIG. 3A shows the third embodiment with photodiodes 9 formed on asubstrate 11. Oxide and metal layers 7 are formed on and aroundphotodiodes 8, 9 and 10. A hard matrix material layer 5 is formed abovethe oxide and metal layers 6. A layer of photo resist 3 is formed abovethe matrix material layer 5. Referring to FIG. 3B, the photo resistlayer 3 is imaged and cavities 27, 28 and 29 are made in the photoresist layer 3 above photodiodes 8, 9 and 10 using a standard resistprocess. As shown in FIG. 3C, the matrix material layer 5 is etched toform cavities 30, 31 and 32 above photodiodes 8, 9 and 10 and the photoresist 3 is stripped from the top of matrix layer 5. Referring to FIG.3D, photo resist 33 is formed into cavities 30, 31 and 32 (FIG. 3C) andonto remaining portions of layer 5 then the photo resist 33 is imagedand etched to reopen cavity 30 above diode 8. Referring to FIG. 3E, afirst color coat 34 (e.g., red) is formed into cavity 31 and onremaining photo resist layer 33. The color coat 34 and photo resist 33is processed by CMP so that the color coat and photo resist 34 isremoved so that the color coat 34 is flush with matrix layer 5 withincavity 30 (FIG. 3C) and photo resist 33 is flush with matrix layer 5within cavities 31, 32 (FIG. 3C) as shown in FIG. 3F. Referring to FIG.3G, photo resist 33 is removed from cavities 31, 32. Photo resist 33 isformed into cavities 31, 32 as well as on matrix layer 5 and first colorlayer 34 as shown in FIG. 3H. The photo resist 33 is then exposed anddeveloped so the photo resist 33 within cavity 31 is opened as shown inFIG. 3I. A second color coating 35 is then applied on top of theremaining photo resist layer 33 and into cavity 31 and the second colorcoating 35 and photo resist 33 which rises above the level of matrixlayer 5 is removed by CMP as shown in FIG. 3J. Referring to FIG. 3K, athird layer of color 37 is formed above the remaining matrix layer 5,color coatings 34, 35 and into cavity 32 (FIG. 3G) then color layer 37is polished by CMP so that the third color layer 37 is flush with matrixlayer 5.

[0077] Referring to FIG. 12, an exemplary process is shown formanufacturing the FIG. 3K structure where all pixels are etched at once.At processing segment S141, an initial film stack (e.g., FIG. 3A) isformed including a substrate 11, photodiodes 8, 9, 10 on or at the topof the substrate 11, a device layer 7 around and above photodiodes 8, 9,10, a hard matrix material layer 5 and then a photo resist layer 3 abovethe hard matrix layer 5. Cavities 27, 28, 29 are formed in photo resistlayer 3 at processing segment S143. At processing segment S145, thematrix layer 5 is etched and stripped to form cavities 30, 31, 32 aboveall photodiodes 8, 9, 10. All photo resist 3 is stripped as well atprocessing segment S145. Standard photo resist 33 (FIG. 3D) is coatedonto the remaining hard matrix layer 5 and into cavities 30, 31, 32 inmatrix layer 5 at processing segment S147. At processing segment S149,the photo resist 33 is exposed and a cavity 30 is formed in the photoresist 33. At processing segment S151, a color coating 34 (e.g., red,blue, green) is applied onto photo resist 33 and into cavity 30. Theapplied color coating 34 is then removed above the level of the hardmatrix layer 5 layer top so that the applied color remaining is previouscavity 30 is flush with the hard matrix layer 5 at processing segmentS153. At processing segment S153, the photo resist 33 in cavitieswithout color coating, i.e., 31, 32 is stripped. At processing segmentS155, a determination of whether or not another color coating is to beapplied is made. If another color coating is to be applied, then anotherdetermination is made as to whether or not the new color coating is afinal color coating at processing segment S157. If the coat to beapplied is not a final coat, then processing continues at processingsegment S147 and continues until processing segment S155 where anotherdetermination of whether or not another color coating is to be applied.If another color coating is to be applied, then another determination ismade at processing segment S157 of whether or not the color coating tobe applied is a final color coating. If the color coating to be appliedis a final color coating, then processing recommences at processingsegment S151 where a final color coating is applied then processingcontinues to processing segment S155 then terminates as there are nofurther color coatings to be applied.

[0078] A fourth embodiment of the invention allows for the adjustment ofthe depths and composition of the color filter to optimize variousoptical characteristics of the pixel array elements. Referring to FIG.4A, an imager chip is formed with bulk silicon 51, photodiodes 52, 53,54 formed on the bulk substrate 51, a device stack and electricalcomponents 55 are formed on top of the photodiodes 52, 53, 54. Thedevice stack 55 is planarized to smooth it, then a damascene layer 57 isformed above the device stack 55 to a desired initial depth. As shown inFIG. 4A, a standard simplified CMOS imager circuit is formed withphotodiodes 52, 53, 54, interconnects and transistors without the needfor various depths to the photodiodes in combination with a variety ofother circuit or substrate elements which are varied as well.

[0079] Referring to FIG. 4B, the photo resist layer 59 is imaged and acavity 60 is formed in the resist 59 above a photodiode, e.g., 54. Thedepths of the cavities formed into the damascene layer 57 in this andsubsequent processing, and the device layer 25 if required, isdetermined by well known formulas and principles used to optimizeoptical properties of the layers with respect to a color wavelengthwhich a diode in question is designed to sense including intensity orreflectivity of incident light. Determination of optical properties oflayers is well known in the art and is in part described above.Referring to FIG. 4C, the photo resist 59 is etched to form a cavity 60′in the damascene layer 57 for the color filter being constructed.Referring to FIG. 4D, photo resist 59 is formed into cavity 60′. Then,another cavity is formed into the photo resist 59 above anotherphotodiode, e.g., 52, then the hard matrix layer 5 and the device layer7 is etched to form another cavity 63. The depth of the cavity 63 abovephotodiode 52 is determined to optimize incident light on photodiode 52.Referring to FIG. 4E, another layer of photo resist 59 is formed intothe cavity 63 above photodiode 53 then another cavity 65 is formed abovethe remaining photodiode 53 with a depth which is determined to optimizeincident light on photodiode 53. Referring to FIG. 4F, photo resist 59is stripped from the top of hard matrix layer 57 as well as cavities60′, 63 and 65. Referring to FIG. 4G, then each cavity, i.e., 60′, 63and 65 is filled with a different color material 71, 73, 75 (e.g., red,blue or green) which corresponds to a cavity which has been optimizedfor a particular color material.

[0080] Depth of etching into the damascene layer 57, as well as aportion of the device stack, is based in part on absorptive andrefractive modeling results. Each cavity has a different dimension dueto the need to vary a CFA window dimension given a desired wavelength oflight that a particular photodiode is expected to process. FIG. 4G showsan exemplary embodiment of completed CFA window cavities into thedamascene layer 57 as well as device stack above each photodiodelocation. In the FIG. 4G exemplary embodiment, each CFA window is thenfilled with a color pigment or filtering material. FIG. 4G shows anexemplary embodiment of completed imager with CFA windows etched andfilled with the appropriate color or filtering substance. In thisembodiment, red is on the left, blue is in the middle and greenfiltering material is used on the right hand side. However, a variety ofcolor schemes and orders of color manufacturing for a given CFA windowcan be used with the invention.

[0081] Referring to FIG. 13, an exemplary process is shown formanufacturing a structure with different CFA window dimensions such asthe structure shown in FIG. 4G. At processing segment S171, an initialfilm stack is formed including a damascene layer 57, a device stackabove photodiodes 55, photodiodes 52, 53, 54 and bulk silicon 51. Atprocessing segment S173, a layer of standard photo resist 59 isdeposited on the damascene layer 57. At processing segment S175, acavity is imaged in the standard photo resist above a photodiode (e.g.,54). At processing segment S177, etching is accomplished into thedamascene 57 and, if necessary, the device layer 55 through the cavity60 in the photo resist to a predetermined depth which optimizes opticalcharacteristics for a particular light wavelength expected to beabsorbed by a photodiode (e.g., 54) underneath the cavity. At processingsegment S179, a determination of whether or not another cavity in thedamascene layer 57 and/or device layer 55 is required. If another cavityis required, then photo resist is applied into the previously etchedcavity 60′ through the photo resist 59 and damascene layer 55 to maskthe etched cavity 60′. Processing segments S175 through S179 are thenrepeated to form cavities 63, 65 which have dimensions that willoptimize the optical properties of the layers above the respectivephotodiodes 52, 53 underneath cavities 63, 65. When it is determined atprocessing segment S179 that no further cavities are needed in thedamascene 57 and/or device stack 55, then processing commences atprocessing segment S183 where a coating is applied into a cavity whichhas been formed to receive a particular color wavelength. At processingsegment S185, the color coating is exposed and developed. At processingsegment S187, the color coating applied at processing segment S187 ispolished by CMP and cleaned. At processing segment S189, a determinationis made of whether or not another color coating is required. If anothercolor coating is required to be formed into a cavity without colormaterial, then processing continues at processing segment S183 throughS189 until no further color coatings are required and processing ceases.

[0082] Many alternative embodiments are possible which employ CFAfilters which are optimized for optical properties using a damascenelayer or variable CFA window dimensions or both. For example, FIG. 5Ashows the addition of a general filtering layer 81 above the devicestack 55 and over a photodiode 53, in this embodiment, tuned for a greenwavelength of light incident to a photo detector through the layersabove photodiode 54. In FIG. 5B, the general filtering layer 81 isplanarized in order to leave a portion of the general filtering layer 81(extended damascene filter layer) extending above the device stack layer55 over one photodiode 53. The device stack 55 or the general filteringlayer 81 depth has a thickness or composition which is optimized ortuned for the initial color which is being formed onto the device stack.Next, in FIG. 5C the extended damascene filter layer 81 remaining afterplanarization is encapsulated with encapsulation material 83.Encapsulation can be accomplished with a variety of materials includinglow temp oxide material, such as dark silicon rich nitride, low tempDARC, TEOS or spin on glass (SOG).

[0083] Referring to FIG. 5D, another general filtering layer is formedon the first layer of encapsulation material 83 then planarized to leavea portion of filtering material 85 (extended damascene filter layer)extending above the device stack 55 over a different photodiode 52. Theextended damascene filter layer 85 in this exemplary embodiment is tunedor optimized for a red filtering material. Additional encapsulationmaterial 87 is formed above the extended damascene filter layer 85 andover the first encapsulation layer 83. Then, another general filteringlayer (e.g., blue) is formed over the surface of the secondencapsulation layer 87, which is above another photodiode location 54without general filtering material, and then etched to form anotherextended damascene filter layer 89.

[0084] In the exemplary embodiment in FIG. 5D, the extended damascenefilter layers 83, 85, 89 as well as the encapsulation layers 83, 87 aredesigned to optimize optical characteristics of one or more layersthrough which light is incident on the photodiodes 52, 53, 54.Encapsulation layers under, for example, the blue extended damascenefilter layer are thicker than the encapsulation layers of the otherextended damascene filter layers. Instead of etching down, thisembodiment involves building substrate up from a node or area to a pointwhere the intensity or other optical property shows a maximum or otherdesirable value. The encapsulation material can be cleared if it isrequired, such as if such removal improves color transmission at thediode light incident surfaces.

[0085] Referring to FIG. 5E, a final coat or layer 90 is placed on topof the encapsulation material. In some embodiments, a micro lens isplaced on top of the encapsulation material, which can be an opticallyclear material. FIG. 5E shows an embodiment with an encapsulation schemewhich employs a uniform encapsulation material 90 which is placed aboveand around all extended damascene filter layers 81, 85, 89 and thinencapsulation layers 83, 87.

[0086] Referring to FIG. 14, an exemplary process is shown formanufacturing a structure with variable damascene filter structuresresulting in optimized optical properties for layers above a particularphotodiode such as, for example, the exemplary structure shown in FIG.5D. At processing segment S201, an initial film stack is formedincluding a device stack 55 above photodiodes 52, 53, 54 which areemplaced on or above bulk silicon 51. At processing segment S203, alayer of color filter material 81 is deposited on the device stack 55.At processing segment S205, the color filter material layer 81 is formedinto an extended damascene filter layer 81. At processing segment S207,a determination is made of whether or not the color material applied andformed in processing segments S203-S205 is the final color coating. Ifadditional color coatings are to be applied, the processing continues atprocessing sequence S209 where an encapsulation layer 83 is formed witha predetermined depth which optimizes optical properties of layers abovea selected photodiode (e.g., 52) for a particular wavelength of lightincident to the selected photodiode (e.g., 52). At processing segment211, a determination of whether or not another color is to be applied.If another color layer (e.g., 85) requires application, then processingcontinues at processing segment S203 and continues through S209. If acolor layer applied in processing segments 203 and formed in S205 is thefinal color layer, then processing branches to processing segment S209which then terminates processing.

[0087] Referring to FIG. 6A-6G, another exemplary embodiment includesthe extended damascene layers or extrusions without the encapsulationlayers 83, 87. FIG. 6A shows the addition of a general filtering layer91 above the device stack 55. In FIG. 6B, the general filtering layer inthis embodiment is tuned for green wavelength of light. In FIG. 6B, thegeneral filtering layer 91 is planarized in order to leave a portion ofthe general filtering layer 91 (extended damascene layer) extendingabove the device stack layer 55 over one photodiode 53. Next, in FIG. 6Canother general filtering layer 93 tuned to a different lightwavelength, e.g., red, is formed on the device layer over anotherphotodiode 52. Referring to FIG. 6D, the second general filtering layer93 is planarized to leave a portion of filtering material 93 (extendeddamascene layer) extending above the device stack 55 over a differentphotodiode 52. Referring to FIG. 6E, another general filtering layer 95(e.g., blue) is formed over the surface the device stack 55 and theextended damascene layers 91, 93 previously formed. In FIG. 6F, thegeneral filtering material which is tuned, in this example for bluewavelength of light is planarized to form another extended damascenelayer 95 which is above another photodiode location 54. Referring toFIG. 6G, an encapsulation material 97 is formed over the extendeddamascene layers as well to serve a variety of functions includingfurther alterations of the optical properties of the combined layersthrough which light must pass above a particular photodiode.

[0088] Referring to FIG. 15, another exemplary process is shown formanufacturing a structure with variable filter structures resulting inoptimized optical properties for layers above a particular photodiodesuch as, for example, the exemplary structure shown in FIG. 6F. Atprocessing segment S221, an initial film stack is formed including adevice stack 55 above photodiodes 52, 53, 54 which are emplaced on orabove bulk silicon 51. At processing segment S223, color material isdeposited on the device stack 55 to a predetermined depth whichoptimizes color layer (e.g., 91) for a particular wavelength of lightwhich is incident to a selected photodiode surface (e.g., 53). Atprocessing segment S225, the color material layer (e.g., 91) is formedinto an extended filter layer over the selected photodiode (e.g., 53) bymethods such as planarization. At processing segment S227, adetermination is made of whether or not anther color is to be depositedand planarized. If another color is to be deposited on one or moreportions of the imager, then processing segment S223 is accomplished andanother color material layer (e.g., 93) is deposited on the device stack55 and the color material which was previously formed on the devicelayer (e.g., 91) to a predetermined depth. At processing segment S225,the newly deposited color material layer (e.g., 93) is formed into anextended filter layer over the selected photodiode (e.g., 52).Processing continues from processing segment S223 to S227 until noadditional color material layers are to be deposited then processingterminates.

[0089] Referring to FIG. 7A, another exemplary embodiment is shown whichcombines multiple depths or dimensions of a color filter array element93, 91 or 95 with varied location of a respective element with respectto a device layer 55 and a particular photodiode. FIG. 7B shows the useof a damascene layer 57 above the device layer 55 involving variousdimensioned color filter elements 91, 93, 95 with extended damascenelayers. Color filter element dimensions within damascene layer 57 aredetermined such that passage of a particular wavelength of light throughthe layers over a photodiode beneath an element is optimized. FIG. 7Cshows how a micro lens 99 can be used over an exemplary embodiment whichemploys optimized color filter elements with a damascene layer. Itshould be noted that a micro lens 99 may be used with any of theexemplary embodiments of the invention described herein.

[0090] The sequence in which color filters are formed can be varied. Forexample, in some of the exemplary embodiments, red is formed, thengreen, then blue. However, the order of color filter formation is notlimited to this sequence in this, or any other embodiments. It shouldalso be noted that the encapsulation layers can be used with or withoutan embodiment of the invention to further tune and adjust the opticalproperties of an imager.

[0091] Various materials, coatings and dimensions of CFA windows can beused with the invention to optimize optical properties. An extendeddamascene layer can be formed, planed, then can be coated with a coatinglayer which is selected to provide selective alterations to thecumulative reflective and absorptive properties of the layers above aparticular photodiode being tuned. It should be further noted that theinvention is not limited to use of color filtering photo resist asmaterial selection is not limited by ability to be imaged by light.Color filtering polymer material can also be used in place of colorfiltering photo resist.

[0092] The use of variable dimensioned CFA windows above either thedevice stack layer or photodiodes themselves provides a means foradjusting optical properties of an imager based on model data andcollective layer properties. Optical properties include focal,absorptive thin film interference and refractive properties of thecombined layers. Optimization effects include increasing light intensityfor each wavelength incident to a particular diode. Each CFA window canalso be designed to tune or optimize light intensity transmitted indifferent materials for different frequencies. In other words, thedepths of the CFA windows are, in part, dependent on the refractiveindex of the dopants and filler implanted in the CFA windows.Accordingly, various depths of different materials can be used in orderto obtain the appropriate effect or maximum intensity in the photo diodecollection area.

[0093] Another aspect of the invention focuses on how different colorscan be optimized so that each one is delivered with maximum efficiencythrough the substrate to the photodiode. Differently dimensionedmaterials can also include pigments or dye which is capable of optimizedfiltering through imager layers for a particular color. A color or dyecan be formed into a cavity which has different optical path lengthsthat are compatible with the average wavelength expected to pass throughthe path as well as the imager substrate or stack above the photodiode.Tuning the stack thickness to minimize reflection and absorption in thestack for each wavelength range of interest increases the intensity ofthe light collected by a photodiode, usually red, green and blue or cyanmagenta and yellow.

[0094] A variety of etching strategies can be used with the invention.For example, referring to FIG. 8, a set of oxide layers, such as silicondioxide, with various etch stops between oxide layers is provided.Etching can be done on the first oxide layer OX₁ 100 to the first etchstop N₁ 101. Then, the etching chemistry is switched to a differentchemical etch to break through the N₁ 101 etch stop then the etchingchemistry is switched to another chemical etch to etch through a secondoxide layer OX₂ 102 until etch stop N₂ 103 is reached. Then, anotherswitch is made to an etching chemistry which is capable of etchingthrough the second etch stop N₂ 103 if necessary. Then, etching can bedone to the third oxide layer OX₃ 105 to etch stop N₃ 105 which, in thisexample, is above bulk silicon 106 but could also be located inproximity to a photodiode or photo sensitive region. An initial filmstack can include etch stops between each layer or selected layers. Allthree layers can be etched at the same time, then resulting cavitieswhich have been etched to a maximum desired depth can be masked in orderto proceed with etching if necessary. Different layers can be the samematerial or different materials which are sensitive to different etchchemistries, or selective etches of different oxides. Also, it ispossible to perform one photo step and expose different layers.

[0095] Various thicknesses can be used with the different layers indifferent embodiments depending on what layer material is used. Forexample, if silicon nitride is used, a 500 Angstroms thickness can beused for the etch stop. If other materials are used, then thinnerthicknesses may be permissible. Also, it is possible to use differentmaterials with different oxide layers each having their own selectivechemistries. If a selective etch is desired with a sensitivity todifferent etching chemistries, then an etching process which may be usedincludes exposing a layer to create cavities above all photodiodes atonce, then etching all cavities at the first layer or depth at the sametime, then mask the cavities which have reached a maximum desired depth,with or without etch stops. Then, if necessary, an etch stop can beetched through, then apply chemistry etching for a second layer to etchdown to a desired depth or dimension. If necessary, the etching,chemistry switch, etching, masking and etching process can be repeateduntil each color filter cavity has been etched to a desired dimension.

[0096] The pixel structure herein can be incorporated into an imagerdevice having an array of pixels, at least one of the pixels being apixel structure constructed according to the invention. The imagerdevice 109 itself may be coupled to a processor 109 to form a processorsystem 107 as is shown in FIG. 9. Processor system 107 is exemplary of asystem having digital circuits which could receive the output of animager device 109, including a CMOS or CCD image device. Without beinglimiting, such a system can include a computer system, camera system,scanner, machine vision, vehicle navigation system, video phone,surveillance system, auto focus system, star tracker system, motiondetection system, image stabilization system and data compression systemfor high definition television, all of which can utilize the presentinvention.

[0097] A processor based system, such as a computer system for example,generally comprises, in addition to an imager 109, a central processingunit and storage device 108, for example a microprocessor thatcommunicates with one or more input/output devices 110. The imagercommunicates with the processor 108 over a bus or other conventionalcommunication path. It may also be desirable to integrate the processor108, image device 109 and any other required components, such asinput/output device 110, onto a single chip.

[0098] Reference is made to various specific embodiments of theinvention. These embodiments are described with sufficient detail toenable those skilled in the art to practice the invention. It is to beunderstood that other embodiments of the invention may be employed andthat structural and electrical changes may be made without departingfrom the scope or spirit of the present invention.

What is claimed as new and desired to be protected by Letters Patent ofthe United States is:
 1. An imaging device comprising: a plurality ofphoto sensitive regions for receiving incident light; at least one ormore other layers formed on or around said plurality of photo sensitiveregions; a first layer formed above said at least one or more otherlayers; and a plurality of filter regions formed in said first layerabove corresponding ones of said plurality of photo sensitive regions,wherein each of said filter regions has different optical properties forselectively modifying optical characteristics of light passing throughthe filter regions and received by the photo sensitive regions.
 2. Animaging device of claim 1 wherein said plurality of filter regionscomprises first, second and third filter regions, and said plurality ofphoto sensitive regions comprises first, second and third photosensitive regions for respectively receiving first, second and thirdincident light, said first filter region being optimized for said firstincident light, said second filter region is optimized for said secondincident light and said third filter region is optimized for said thirdincident light.
 3. An imaging device of claim 2 wherein said firstfilter region is optimized for a green wavelength of light, said secondfilter region is optimized for a red wavelength of light and said thirdfilter region is optimized for a blue wavelength of light.
 4. An imagingdevice of claim 2 wherein said first filter region is optimized for acyan wavelength of light, said second filter region is optimized for amagenta wavelength of light and said third filter region is optimizedfor a yellow wavelength of light.
 5. An imaging device of claim 2wherein said first, second and third filter regions have respectivefirst, second and third dimensions which are based in part on optimizinglight received by said respective said first, second and third photosensitive regions.
 6. An imaging device of claim 2, wherein said first,second and third filter regions comprise color filter regions formed,respectively, of first, second and third photo sensitive colormaterials.
 7. An imaging device of claim 6, wherein said first, secondand third color filter regions comprise a color filtering photo resist.8. An imaging device comprising: a plurality of color pixels forreceiving incident light; at least one or more other layers formed on oraround said plurality of color pixels; a first layer formed above saidat least one or more other layers; and a plurality of filter regionsformed in said first layer above corresponding ones of said plurality ofcolor pixels, wherein each of said filter regions has different opticalproperties for selectively modifying optical characteristics of lightpassing through the filter regions and received by the color pixels. 9.An imaging device of claim 8, wherein at least one of said filterregions comprises a photo lithographic material.
 10. An imaging deviceof claim 8, wherein at least one of said filter regions are formedwithin previously defined openings in said first layer.
 11. An imagingdevice of claim 8 wherein said plurality of color pixels comprise first,second and third color pixels for respectively receiving first, secondand third incident light, and said filter regions comprise first, secondand third filter regions which are respectively optimized for saidfirst, second and third incident light.
 12. An imaging device of claim11 wherein said first filter region is optimized for a green wavelengthof light, said second filter region is optimized for a red wavelength oflight and said third filter region is optimized for a blue wavelength oflight.
 13. An imaging device of claim 11 wherein said first filterregion is optimized for a cyan wavelength of light, said second filterregion is optimized for a magenta wavelength of light and said thirdfilter region is optimized for a yellow wavelength of light.
 14. Animaging device of claim 11 wherein said first, second and third filterregions have a respective first, second and third dimension forselectively altering the intensity of said incident light received bysaid first, second and third color pixels.
 15. A color pixel for animaging device, said comprising: a plurality of photo sensitive regionsfor receiving incident light; a first layer formed above said photosensitive regions; and a plurality of filter regions formed in saidfirst layer above corresponding ones of said plurality of photosensitive regions, wherein each of said filter regions has differentoptical properties for selectively modifying optical characteristics oflight passing through the filter regions and received by the photosensitive regions.
 16. A color pixel of claim 15 wherein said pluralityof filter regions comprises first, second and third filter regions, andsaid plurality of photo sensitive regions comprises first, second andthird photo sensitive regions for respectively receiving first, secondand third incident light, said first filter region being optimized forsaid first incident light, said second filter region is optimized forsaid second incident light and said third filter region is optimized forsaid third incident light.
 17. A color pixel of claim 16 wherein saidfirst filter region is optimized for a green wavelength of light, saidsecond filter region is optimized for a red wavelength of light and saidthird filter region is optimized for a blue wavelength of light.
 18. Acolor pixel of claim 16 wherein said first filter region is optimizedfor a cyan wavelength of light, said second filter region is optimizedfor a magenta wavelength of light and said third filter region isoptimized for a yellow wavelength of light.
 19. A color pixel of claim16 wherein said first, second and third filter regions have a respectivefirst, second and third dimension for optimizing the incident lightreceived, respectively, by said first, second and third photo sensitiveregion.
 20. An imaging device comprising: a plurality of photo sensitiveregions for receiving incident light; a plurality of damascene layersformed respectively above said plurality of photo sensitive regions; anda plurality of filter regions respectively formed above said pluralityof damascene layers and said plurality of photo sensitive regions, eachof said filter regions and said damascene layers having opticalproperties for modifying the optical properties of said incident lightreceived by said respective photo sensitive region.
 21. An imagingdevice of claim 20, wherein said plurality of filter regions comprisesfirst, second and third filter regions, and said plurality of photosensitive regions comprises first, second and third photo sensitiveregions for respectively receiving first, second and third incidentlight, said first filter region being optimized for said first incidentlight, said second filter region is optimized for said second incidentlight and said third filter region is optimized for said third incidentlight.
 22. An imaging device of claim 21, wherein said first filterregion is optimized for a green wavelength of light, said second filterregion is optimized for a red wavelength of light and said third filterregion is optimized for a blue wavelength of light.
 23. An imagingdevice of claim 21 wherein said first filter region is optimized for acyan wavelength of light, said second filter region is optimized for amagenta wavelength of light and said third filter region is optimizedfor a yellow wavelength of light.
 24. An imaging device of claim 21wherein said first, second and third filter regions have respectivefirst, second and third dimensions for optimizing the incident lightreceived by said first, second and third photo sensitive regions,respectively.
 25. An imaging device comprising: a plurality of photosensitive regions for receiving incident light; a first layer formedabove said photo sensitive regions; and a plurality of filter regionsformed in said first layer above corresponding ones of said plurality ofphoto sensitive regions, wherein each of said filter regions hasdifferent optical properties for selectively modifying opticalcharacteristics of light passing through the filter regions and receivedby the photo sensitive regions.
 26. An imaging device of claim 25wherein said plurality of filter regions comprises first, second andthird filter regions, and said plurality of photo sensitive regionscomprises first, second and third photo sensitive regions forrespectively receiving first, second and third incident light, saidfirst filter region being optimized for said first incident light, saidsecond filter region is optimized for said second incident light andsaid third filter region is optimized for said third incident light. 27.An imaging device of claim 26 wherein said first filter region isoptimized for a green wavelength of light, said second filter region isoptimized for a red wavelength of light and said third filter region isoptimized for a blue wavelength of light.
 28. An imaging device of claim26 wherein said first filter region is optimized for a cyan wavelengthof light, said second filter region is optimized for a magentawavelength of light and said third filter region is optimized for ayellow wavelength of light.
 29. An imaging device of claim 26 whereinsaid first, second and third filter regions have respective first,second and third dimensions for optimizing light received by said first,second and third photo sensitive regions, respectively.
 30. A colorpixel for an imaging device, said pixel comprising: a plurality of photosensitive regions for receiving incident light; a first layer formedabove said photo sensitive regions; and a plurality of filter regionsformed in said first layer above corresponding ones of said plurality ofphoto sensitive regions, wherein each of said filter regions hasdifferent optical properties for selectively modifying opticalcharacteristics of light passing through the filter regions and receivedby the photo sensitive regions.
 31. A color pixel of claim 30 whereinsaid plurality of filter regions comprises first, second and thirdfilter regions, and said plurality of photo sensitive regions comprisesfirst, second and third photo sensitive regions for respectivelyreceiving first, second and third incident light, said first filterregion being optimized for said first incident light, said second filterregion is optimized for said second incident light and said third filterregion is optimized for said third incident light.
 32. A color pixel ofclaim 31 wherein said first filter region is optimized for a greenwavelength of light, said second filter region is optimized for a redwavelength of light and said third filter region is optimized for a bluewavelength of light.
 33. A color pixel of claim 31 wherein said firstfilter region is optimized for a cyan wavelength of light, said secondfilter region is optimized for a magenta wavelength of light and saidthird filter region is optimized for a yellow wavelength of light.
 34. Acolor pixel of claim 31 wherein said first, second and third filterregions have respective first, second and third dimensions foroptimizing the incident light received by said first, second and thirdphoto sensitive regions, respectively.
 35. A computer system,comprising: a bus; a processor coupled to said bus; an input/outputdevice coupled to said bus; an imaging device coupled to said bus and incommunication with said processor and input/output device comprising: aplurality of photo sensitive regions for receiving incident light; atleast one or more other layers formed on or around said plurality ofphoto sensitive regions; a first layer formed above said at least one ormore other layers; and a plurality of filter regions formed in saidfirst layer above corresponding ones of said plurality of photosensitive regions, wherein each of said filter regions has differentoptical properties for selectively modifying optical characteristics oflight passing through the filter regions and received by the photosensitive regions.
 36. A computer system of claim 35 wherein saidplurality of filter regions comprises first, second and third filterregions, and said plurality of photo sensitive regions comprises first,second and third photo sensitive regions for respectively receivingfirst, second and third incident light, said first filter region beingoptimized for said first incident light, said second filter region isoptimized for said second incident light and said third filter region isoptimized for said third incident light.
 37. A computer system of claim36 wherein said first filter region is optimized for a green wavelengthof light, said second filter region is optimized for a red wavelength oflight and said third filter region is optimized for a blue wavelength oflight.
 38. A computer system of claim 36 wherein said first filterregion is optimized for a cyan wavelength of light, said second filterregion is optimized for a magenta wavelength of light and said thirdfilter region is optimized for a yellow wavelength of light.
 39. Acomputer system of claim 36 wherein said first, second and third filterregions have respective first, second and third dimensions which arebased in part on optimizing light received by said respective saidfirst, second and third photo sensitive regions.
 40. A computer systemof claim 36, wherein said first, second and third filter regionscomprise color filter regions formed, respectively, of first, second andthird photo sensitive color materials.
 41. A computer system of claim36, wherein said first, second and third color filter regions comprise acolor filtering photo resist.
 42. A computer system, comprising: a bus;a processor coupled to said bus; an input/output device coupled to saidbus; an imaging device coupled to said bus and in communication withsaid processor and input/output device comprising: a plurality of colorpixels for receiving incident light; at least one or more other layersformed on or around said plurality of color pixel; a first layer formedabove said at least one or more other layers; and a plurality of filterregions formed in said first layer above corresponding ones of saidplurality of color pixels, wherein each of said filter regions hasdifferent optical properties for selectively modifying opticalcharacteristics of light passing through the filter regions and receivedby the color pixels.
 43. A computer system of claim 42 wherein saidplurality of filter regions comprises first, second and third filterregions, and said plurality of color pixels comprise first, second andthird color pixels for respectively receiving first, second and thirdincident light, said first filter region being optimized for said firstincident light, said second filter region is optimized for said secondincident light and said third filter region is optimized for said thirdincident light.
 44. A computer system of claim 43 wherein said firstfilter region is optimized for a green wavelength of light, said secondfilter region is optimized for a red wavelength of light and said thirdfilter region is optimized for a blue wavelength of light.
 45. Acomputer system of claim 43 wherein said first filter region isoptimized for a cyan wavelength of light, said second filter region isoptimized for a magenta wavelength of light and said third filter regionis optimized for a yellow wavelength of light.
 46. A computer system ofclaim 43 wherein said first, second and third filter regions haverespective first, second and third dimensions which are based in part onoptimizing light received by said respective said first, second andthird color pixels.
 47. A computer system of claim 43, wherein saidfirst, second and third filter regions comprise color filter regionsformed, respectively, of first, second and third photo sensitive colormaterials.
 48. A computer system of claim 43, wherein said first, secondand third color filter regions comprise a color filtering photo resist.49. A method of manufacturing a color pixel for an imaging device,comprising: forming a first layer above a plurality of first, second andthird photo sensitive regions for respectively receiving a first, secondand third incident light; and forming sequentially first, second andthird light filter regions in said first layer, each of said filterregions being selectively formed to have a color and a depth such thatthe incident light received by said respective said first, second andthird regions is modified to a predetermined intensity value foroptimizing performance of said photosensitive regions.
 50. A method ofmanufacturing of claim 49 wherein said color is a photo lithographicmaterial.
 51. A method of manufacturing an imaging device, comprising:forming a first plurality of openings in a first layer above acorresponding first plurality of photo sensitive areas in an imager die;coating said die with a first color filter material; removing excesscolor material above the top level of said die; and forming anotherplurality of openings in said first layer above another correspondingplurality of photo sensitive areas in said imager die; coating said diewith a second color filter material; and removing excess color materialabove the top level of said die; wherein each of said openings is formedto a predetermined depth based upon the desired intensity of light to bepassed through said respective color material and underlying layer, andreceived by said corresponding photo sensitive areas.
 52. A method ofmanufacturing as in claim 51 further comprising: forming anotherplurality of openings in said first layer above another plurality ofphoto sensitive areas in said imager die; coating said die with a thirdcolor filter material; and removing excess color material above the toplevel of said die.
 53. A method of manufacturing a color pixel for animaging device, comprising: forming an initial film stack includingphoto resist, a hard matrix layer, and at least one layer including aplurality of photodiodes; forming an opening in said photo resist aboveat least one of said photodiodes; etching and stripping said hard matrixmaterial above said at least one photodiode to form an opening abovesaid at least one photodiode; applying a color material into said etchedopening; and performing chemical mechanical polishing to remove excesscolor material above the top level of said matrix layer.
 54. A method ofmanufacturing a color pixel for an imaging device, comprising: applyingphoto resist onto a die; forming an opening in photo resist above aphoto sensitive area on said die; removing material underneath saidopening in said photo resist to a predetermined depth based upon thedesired optical properties of light to be received by said photosensitive area; applying a color filter coating over said die and intosaid opening; and removing color filter coating and photo resist abovetop surface of said die.
 55. A method of manufacturing a color pixel ofclaim 54, further comprising: repeating the steps of applying photoresist, removing material, applying a color coating and removing colorfilter coating steps for each additional color filter material to beapplied to said die.
 56. A method of manufacturing a color pixel for animaging device, comprising: applying photo resist onto a die; forming aplurality of openings in photo resist above a plurality of photosensitive areas on said die; removing material underneath said openingin photo resist to a selected depth based upon desired lighttransmission properties for a particular wavelength of light to bereceived by said plurality of light sensitive areas; applying a colorfilter coating over said die and into said openings; and removing colorfilter coating and photo resist above top surface of said die.
 57. Amethod of manufacturing a color pixel of claim 56, further comprising:repeating said steps of applying photo resist, removing material,applying a color coating and removing color filter coating steps foreach additional color filter material to be applied to said die.
 58. Amethod of manufacturing a color pixel for an imaging device, comprising:applying photo resist onto a die; forming a plurality of openings inphoto resist above a photo sensitive area on said die; removing materialunderneath said openings in photo resist to a predetermined depth basedupon desired properties of light to be received by said photo sensitivearea; applying a color filter coating over said die and into saidopenings; and removing color filter coating and photo resist above topsurface of said die.
 59. A method of manufacturing a color pixel ofclaim 58, further comprising: repeating said steps of applying photoresist, removing material, applying a color coating and removing excesscolor filter coating for each additional color filter material to beapplied to said die.
 60. A method of manufacturing a color pixel for animaging device, comprising: forming sequentially a plurality of colorfilter regions respectively above a corresponding plurality of photosensitive areas on a die; and applying a layer of encapsulation materialafter each application of a color filter region, said encapsulationmaterial formed to a depth based upon desired properties of light to bereceived by said photo sensitive areas.
 61. A method of manufacturing acolor pixel of claim 60 wherein said color filter regions comprisegroups of first, second and third color materials.
 62. A method ofmanufacturing a color pixel for an imaging device, comprising: formingsequentially a plurality of color filter regions respectively above aplurality of photo sensitive areas on a die, said regions formed on topof a layer above said photo sensitive areas, wherein said color filterregions comprise groups of first, second and third color materials withdifferent depths, said depths determined based upon desired propertiesof light to be received by said photo sensitive areas.
 63. A method asin claim 62 wherein said first color material is formed to optimizeintensity of a green wavelength of light, said second color material isformed to optimize intensity of a red wavelength of light and said thirdcolor material is formed to optimize intensity of a blue wavelength oflight.
 64. A method as in claim 62 wherein said first color material isformed to optimize intensity of a cyan wavelength of light, said secondcolor material is formed to optimize intensity of a magenta wavelengthof light and said third color material is formed to optimize intensityof a yellow wavelength of light.